Evaluation approaches

1. Evaluation approaches Text p 340 - 347 Text p 590- 595

2. Evaluation approaches • Usability testing • Field studies • Analytical evaluation • Combining approaches • Opportunistic evaluations

3. Usability testing • Dominant approach in the 80’s • Involves measuring typical users performance on typical tasks • Note the number and types of errors that users make and record the time it takes them to complete the task • Recorded on video/audio with interactions often recorded • User satisfaction questionnaires and interviews are also used to elicit user opinions • Test environment and format of testing is controlled by the valuator

4. Field studies • Done in natural setting with the aim of understanding what people do naturally and how products mediate their activities • Help identify opportunities for new technology • Establish the requirements for design • Facilitate the introduction of technology or how to deploy existing technology in new contexts • Evaluate technology

5. Analytical evaluation • 2 categories: • inspections • heuristic evaluation • Walkthroughs • theoretical based models • keystroke model • Fitt’s Law

6. Analytical evaluation Heuristics • Based on common sense knowledge and usability guidelines • Originally developed for screen based applications • Adapted to make new sets for evaluation web based products, mobile devices and computerised toys • Care needs to be taken as designers are sometimes led astray by findings from heuristic evaluation that are mot as accurate as they first thought

7. Analytical evaluation Cognitive Walkthroughs • Involve simulating a users problem solving process at each step in the human computer dialog and checking to see how users progress from step to step in these interactions • Focus on evaluation designs for ease of learning • Other walkthroughs developed: pluralistic

8. Analytical evaluation Predictive models • Have been primarily used for comparing the efficacy of different interfaces for the same application • Eg the optimal arrangement and location of features on the interface base • The keystroke model provides numerical predictions of user performance • Fitt’s Law predicts the time it takes to reach a target using a pointing device

9. Characteristics of approaches

10. Evaluation approaches and methods